Sullivan's Island (copy) (copy)

The beach is a popular spot at Sullivan's Island, which is South Carolina's wealthiest ZIP code based on the percentage of tax filers who report more than $200,000 in annual income to the IRS. File/Staff

The term “1 percenter” doesn’t quite sum up the population of the well-heeled residents in South Carolina.

It understates it.

The source of this statistical tidbit is a federal agency that will be awash in numbers and data as the tax-filing season winds down this week. 

According to the latest figures from the Internal Revenue Service, the top rung of earners — defined as reporting at least $200,000 in annual income — filed slightly more 3 percent of the 2.14 million federal returns that came from the Palmetto State in 2015. That's an impressive 14 percent jump from the previous year.

Joey Von Nessen, a research economist at the University of South Carolina's Moore School of Business, said the increase coincided with a "tipping point for wage growth" in the state.

"I think the data do provide an accurate snapshot," he said.

For inquiring minds, the IRS also provides a peek behind the curtain at where this wealthy clutch of 64,440 tax filers live, without going all Facebook on them. It’s neatly laid out in a series of voluminous spreadsheets that categorize taxpayers nationwide by their ZIP codes and income levels.

"It an interesting report," Von Nessen said Friday. 

The figures show that more individual wealth is bubbling up in South Carolina, even as the overall median income level, while nudging higher, remains among the lowest in the nation.

The average total earnings for the top wage bracket in the state was about $454,000 in 2015, up about $18,000 from 2014, according to the IRS figures.

The high-octane Charleston-area was the equivalent of the mother lode for Uncle Sam. The region claimed six of the top 20 ZIP codes statewide based on the number households that hauled in at least $200,000 in 2015. Close to  10,000 in all.

Leading the pack was Mount Pleasant, the rapidly growing suburb that’s now the fourth-biggest municipality in South Carolina. The town's two ZIP codes were home to nearly 5,000 top-tier earners, making them No. 1 and No. 2 in the state.

Most of South Carolina's major job centers also were represented among the top 20. After Mount Pleasant, South Carolina's richest ZIP codes were in Simpsonville in the Upstate, Lexington in the Midlands and the pricey Tega Cay section of York County.

Rounding out the top 10 were other moneyed mailing addresses: Daniel Island, Hilton Head Island, a portion of Greenville County, Bluffton and the James Island-Folly Beach corridor.

Von Nessen said the source of the wealth differs from place to place.

In the Charleston area, it's likely tied to high-wage jobs in the technology, defense and health-care industries. In Aiken, Bluffton and Hilton Head, it skews more toward rich retirees. In the Upstate, it's mostly tied to advanced manufacturing, which the USC economist called "the major driver of South Carolina's growth in this expansion over the last nine years." 

The IRS data also highlighted how some areas, like the exclusive Lake Keowee-Sunset area in Oconee County, punch above their weight in terms of earnings. But the most striking example is the state's richest ZIP code: Sullivan's Island, where nearly a third of the households reported more than $200,000 in annual income. 

That shouldn't be much of a surprise. The total income for the Lowcountry beach enclave's 980 tax filers came to nearly $345 million in 2015. That was enough to make it the 114th wealthiest ZIP code in the U.S., according to a BloombergPursuits analysis.

Contact John McDermott at 843-937-5572 or follow him on Twitter at @byjohnmcdermott